Friction heater systems have been used with many sources of energy for convenient heating, water-wheels and windmills being examples; particularly in testing, electric motors have been used.
In the prior art, systems have been disclosed in patents for friction heating including the following U.S. and foreign patents;
U.S. Pat. No. 2,090,873 issued to A. Lazarus on 8-24-37 showed conically interfitted friction members for producing hot water or steam using a boiler or tank and a drive motor;
U.S. Pat. No. 4,004,553 issued to L. A. Stenstrom on 1-25-77, showed varieties of a motor driven rotor in a casing shaped with the general contours of the rotor, for heat generation in a fluid by shearing action. FIG. 8 in particular showed a generally conical cup-like rotor, small end down, and similar cup-like conical rotor in FIG. 6 and rounded cup-like conical shape in FIG. 7;
West Germany Pat. No. 2,927,659, July 9, 1979, Jan. 29, 1981, showed truncate-cone interfitting male and female, the male spring-biased; fluid inlet and outlet appear in a boiler-like surround for the female;
Germany Pat. No. 286,747, Dec. 31, 1914; Aug. 27, 1915, showed a conical friction member, evidently manually operated for warming a cup of fluid.
U.S. Pat. No. 4,554,906 issued 11-26-85, to the present inventors for TANKLESS FRICTION BOILER SYSTEM disclosed interfitting cylindrical friction members in a friction heating system.
However, regulation of a system of the type described in vertical embodiments which have advantageous features, has proved to be difficult. Both wear rates and frictional loading can be uneven and can produce, at best, hard starts and other inefficiences in the equipment and in results, and at worst, vibration, seizures and destructive overloads and equipment failure.